Photonic Switch (2 of 2) (IMAGE) University of California - Berkeley Caption The photonic switch is manufactured using a technique called photolithography, in which each "light switch" structure is etched into a silicon wafer. Each light gray square on the wafer contains 6,400 of these switches. Credit Kyungmok Kwon photo Usage Restrictions with credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.